Feasibility of using straw in a strong, thin, pulp moulded packaging material

Packaging is a ubiquitous commodity that is being used in increasing quantities. This increased use has led to a problem with disposal, with increased quantities of used packaging being sent to landfill. One sustainable solution suggested is the use of biobased, biodegradable packaging. An example of this is paper based pulp moulded products which have been used previously for a number of packaging applications. In this paper the feasibility of replacing paper fibre with waste cereal straw fibre is examined. The aim was to produce materials that could be used to form flat, round trays, such as those used in supporting shrink wrapped food items. The material was required to have properties that matched existing alternatives, such as expanded polystyrene, in terms of physical and mechanical characteristics but with an enhanced level of biodegradability. The data showed that the pulp moulded material containing up to 80% straw performed significantly better compared to expanded polystyrene in tensile properties (modulus of 0.47 MPa for an 80% straw mix compared to 0.16 MPa for EPS). Modulus under bending was shown to be lower for straw based materials compared to EPS (0.015 MPa compare to 0.035 MPa). Adjustments in product thickness allowed performance parameters to be met. Wet end addition of chemicals was successfully used to provide water resistance without affecting other variables. In addition to exhibiting good performance characteristics the pulp moulded material was shown to be biodegradable, exhibiting 20% mass loss after only 4 weeks covered in unsterile soil.